A method of liquid sulfur direct injection into a fuming furnace for sulfurization and volatilization

Abstract

The application discloses a method for directly injecting liquid sulfur into a fuming furnace for vulcanization and volatilization, which can ensure smooth pipeline transportation of liquid sulfur, which is a vulcanizing agent, and the prepared control of the feeding speed of the liquid sulfur, avoid the technical problems of waste caused by direct combustion of granular sulfur and easy blockage of the pipeline caused by direct injection of the granular sulfur, and realize the full vulcanization-reduction combined reaction by setting the reasonable position of the granular sulfur in the fuming furnace and the pulverized coal burner, so that the best economic index of the liquid sulfur and the pulverized coal can be controlled.

Description

A method for direct injection of liquid sulfur into a fuming furnace for sulfur volatilization. Technical Field

[0001] This invention relates to the field of sulfidation-reduction technology in tin-containing material fuming furnaces, and more specifically to a method for the direct injection of liquid sulfur into a fuming furnace for sulfidation and volatilization. Background Technology

[0002] As the tin content of tin ore raw materials decreases year by year and their composition becomes increasingly complex, the improvement of processing technology for tin-containing materials is urgently needed. Fuming furnaces, as equipment widely used in the sulfidation and volatilization treatment of tin-containing materials, have been in use for over half a century and have accumulated extremely mature and rich production and operation experience. Historically, the industry has primarily used pyrite (also called iron ore) as a sulfidation and volatilization agent for tin-containing materials, mainly because pyrite is widely available and relatively inexpensive.

[0003] Pyrite, used as a sulfidation volatilization agent in fuming furnaces, is typically fed into the furnace via a conveyor belt at the top. It reacts with the high-temperature molten metal inside the furnace to undergo a sulfidation reaction. The sulfur in the pyrite reacts with tin oxide (SnO2, SnO), and the main reactions are as follows:

[0004] 2(FeS2) + O2 = 2(FeO) + 4(S) (1)

[0005] (SnO2)+2(S)= SnS(g)+SO2(g) (2)

[0006] 2(FeO) + SiO2 = 2FeO•SiO2 (3)

[0007] The overall reaction is: 2(FeS2)+O2+2(SnO2)+SiO2=2FeO•SiO2+2SnS(g)+ 2SO2(g) (4)

[0008] 2(SnO)+3(S)=2SnS(g)+SO2(g) (5)

[0009] The overall reaction is: 2(FeS2)+2O2+2(SnO)+SiO2=2FeO•SiO2+2SnS(g)+ 2SO2(g) (6)

[0010] Reaction (1) is the high-temperature oxidation of pyrite, releasing liquid elemental sulfur (S) and (FeO). (FeO) will react with quartz sand SiO2 to form slag (3) and generate ferruginous phase 2FeO•SiO2. The gaseous SnS(g) after the above sulfidation volatilization enters the rising flue and is oxidized by secondary air supply, that is, the following reaction occurs:

[0011] SnS(g) + 2O2 = SnO2(s) + SO2(g) (7)

[0012] Tin will be collected in the surface cooler and bag filter as solid tin dioxide (SnO2(s)) and used as a raw material for subsequent smelting processes.

[0013] However, it can be seen from the above general reactions (4) and (6) that the sulfur utilization rate in pyrite is not high. When two molecules of pyrite react with two different forms of tin oxide (SnO2, SnO), they release two molecules of sulfur dioxide gas SO2(g). In order to further improve the sulfur utilization rate in pyrite, smelters often need to add a certain amount of pulverized coal (i.e., carbon C). The above general reactions (4) and (6) combined with pulverized coal (i.e., carbon C) will undergo the following reaction:

[0014] 2(FeS2)+O2+4(SnO2)+SiO2+4C(s)=2FeO·SiO2+4SnS(g)+4 CO2(g) (8)

[0015] 2(FeS2)+2O2+4(SnO)+SiO2+3C(s)=2FeO·SiO2+4SnS(g)+3CO2(g) (9)

[0016] The supplemented pulverized coal not only participates in the sulfidation and volatilization reactions of (8) and (9) in the fuming furnace, but also partially reacts with oxygen in the furnace to generate heat through combustion, thus supplementing the heat required for the high-temperature melt to maintain good fluidity and for related chemical reactions. In other words, the carbon in the pulverized coal plays a dual role in both the sulfidation reaction and the heat generation through combustion.

[0017] Nevertheless, the above-mentioned reactions will occur during the sulfidation and volatilization process of tin-containing materials in the fuming furnace. However, the pyrite purchased by the factory usually contains at least 10% moisture by mass. This moisture is difficult to further dehydrate and dry, otherwise the sulfur in the pyrite will be lost due to the evaporation water, which is very uneconomical for the smelter. When this moisture enters the fuming furnace along with the pyrite, the following reactions will occur under high temperature conditions:

[0018] (FeS2)+2H2O=2H2S(g)+(FeO) (10)

[0019] The hydrogen sulfide gas H2S(g) released in the above reaction will quickly escape from the molten pool into the flue gas. Except for a small amount of hydrogen sulfide gas H2S(g) undergoing oxidation and combustion in the high-temperature zone to produce sulfur dioxide and water, most of the hydrogen sulfide gas H2S(g) does not participate in other reactions. This directly leads to low sulfur utilization in pyrite. From reaction (10), it can be calculated that 10% water by mass will consume 33.3% pyrite by mass, which will directly lead to unsatisfactory smelting economic indicators. In addition, the residual hydrogen sulfide gas H2S(g) in the flue gas will also affect subsequent flue gas acid production or desulfurization treatment. Improper treatment will result in the tail gas exhaust having a strong "rotten egg" smell, polluting the atmosphere.

[0020] Therefore, this invention proposes a method for directly using liquid sulfur as a sulfiding agent to volatilize tin-containing materials in fuming furnaces. This method explores the use of sulfur as a sulfiding agent to replace pyrite, avoiding the aforementioned technical problems and solving the technical difficulty of clogging pipelines when using pneumatic conveying of powdered sulfur. Research shows that currently in China, only in the impurity removal processes of crude tin refining, crude lead refining, and crude nickel refining, most industries use granular sulfur added to high-temperature crude metal to remove copper impurities. The sulfur in the sulfur reacts with the impurity copper to form insoluble solid copper sulfide. This solid copper sulfide condenses during the cooling process, and after slag removal, it is separated, thus achieving the removal of impurity copper. However, this granular sulfur is generally added from the surface of the high-temperature crude metal melt and, after stirring, is drawn into the interior of the melt to participate in the reaction. However, in the sulfidation and volatilization treatment of tin-containing materials in a fuming furnace, sulfur is directly added to the molten pool as a sulfiding agent. If sulfur is added to the molten pool via a conveyor belt at the top of the furnace, the sulfur will easily burn at temperatures above 248°C due to the high temperature and oxidizing atmosphere as it falls into the molten pool, directly generating sulfur dioxide. Only a small amount of particulate sulfur may fall into the molten pool to participate in the sulfidation reaction, which will directly lead to a serious lack of effective utilization of particulate sulfur. A few domestic enterprises also use particulate sulfur, which is pneumatically conveyed into the molten pool for sulfidation reaction through pipelines. However, after a period of continuous use, the fine particulate sulfur gradually adheres to the inner wall of the particulate sulfur conveying pipeline, and the effective aperture of the particulate sulfur conveying pipeline becomes smaller and smaller, which inevitably leads to blockage of the pipeline, resulting in poor conveying of particulate sulfur and affecting normal production operations. In addition, the fine particulate sulfur adhering to the inner wall of the pipeline has high hardness and is difficult to clean, which will increase the difficulty and workload of cleaning the particulate sulfur pipeline. There are no reports on the research and industrial application of fuming furnace smelting or other molten pool smelting technologies and equipment, or the use of liquid sulfur as a sulfiding agent to be directly injected into a high-temperature molten pool. Summary of the Invention

[0021] The purpose of this invention is to provide a method for directly injecting liquid sulfur to fumigate and volatilize tin-containing materials, ensuring smooth and unblocked pipeline transportation of the liquid sulfur sulfide, precise control of the liquid sulfur feeding rate, avoiding the waste of direct combustion of particulate sulfur and the technical difficulties of easy pipeline blockage caused by direct injection of particulate sulfur, and setting the reasonable position of particulate sulfur and pulverized coal burners in the fumigate furnace to ensure the full progress of the sulfidation-reduction combined reaction, and achieving optimal control of the economic indicators of liquid sulfur and pulverized coal.

[0022] To achieve the above objectives, the present invention adopts the following technical solution:

[0023] A method for directly injecting liquid sulfur into a fuming furnace for sulfur volatilization includes the following steps:

[0024] (1) Purchased granular sulfur is delivered to the granular sulfur storage silo, and the sulfur is fed into the granular sulfur melting and heat preservation tank by the granular sulfur feeder; turn on the infrared heating melter to heat up and melt the granular sulfur, and control the temperature of the liquid sulfur in the granular sulfur melting and heat preservation tank at 130~150℃; the liquid sulfur suction pump is set at 1 / 3 of the height from the bottom of the tank, and always keeps the molten liquid sulfur in the granular sulfur melting and heat preservation tank at 2 / 3 of the height capacity;

[0025] (2) After the tin ore in the fuming furnace is completely melted, keep the nitrogen supply in the central pipeline of the liquid sulfur injection burner unobstructed and stabilize the nitrogen pressure in the central pipeline nitrogen pipe at 3~6 Bar. Open the check valve of the liquid sulfur delivery pipeline and start the liquid sulfur suction pump to inject liquid sulfur into the fuming furnace. When the weight of the liquid sulfur feed reaches 90% of the calculated amount, take a sample of the molten slag in the fuming furnace and send it for analysis. After the slag tin content is ≤0.2%, stop the liquid sulfur suction pump and discharge the slag to the slag water quenching system. If the slag tin content is higher than 0.2%, take a sample of the molten slag every 1 minute and send it for analysis. After the slag tin content is ≤0.2%, stop the liquid sulfur suction pump and immediately open the slag outlet of the fuming furnace to carry out the slag discharge and water quenching operation.

[0026] (3) Step (2) Start the liquid sulfur suction pump and spray liquid sulfur into the fuming furnace. At the same time, control the pulverized coal conveying and blowing system to feed pulverized coal evenly into the fuming furnace. At the same time, observe the flue gas monitoring at the outlet of the bag dust collector to ensure that the SO2 and CO concentrations in the flue gas during the liquid sulfur injection and pulverized coal feeding process are 0.9~1.5% and 7000~10000ppm, respectively. If the concentrations are lower or higher than the range, the liquid sulfur and pulverized coal feed rates should be increased or decreased respectively, with fine adjustments within ±0.2t / h. Alternatively, the CO concentration can be controlled within the above range by adjusting the opening of the secondary air valve.

[0027] (4) Check the situation inside the fuming furnace through the observation hole. After confirming that the slag inside the furnace has been completely discharged, close the nitrogen delivery valve of the central pipeline, the coal delivery air valve and the check valve of the liquid sulfur delivery pipeline. Disassemble the liquid sulfur injection burner and the pulverized coal injection burner to check and clean the burner blockage. Then reinstall the liquid sulfur injection burner and the pulverized coal injection burner back to their original positions. Keep the central nitrogen delivery and pulverized coal delivery air of the liquid sulfur injection burner in the open state again, keep the check valve of the liquid sulfur delivery pipeline closed, and keep the nitrogen delivery pressure and pulverized coal delivery air stable at 3~6 Bar. Then start the fuming furnace production operation to enter the next cycle.

[0028] Preferably, in step (1), the purchased sulfur contains ≥99% sulfur and the particle size of the purchased granular sulfur is between 2.8 and 6.0 mm;

[0029] The nitrogen gas used in the liquid sulfur injection burner to inject into the fuming furnace in step (2) is pure nitrogen gas, and the water content of the pure nitrogen gas is ≤0.5%.

[0030] Preferably, the parameters of the liquid sulfur suction pump in step (2) are as follows: within 10 minutes of starting the feed head, the feed rate is increased by 0.1 t / h every minute starting from 0 t / h. That is, after 10 minutes of starting, the feed rate of the liquid sulfur suction pump will reach 1.0 t / h, and the feed rate is maintained within 1.0 ± 0.2 t / h with slight adjustments.

[0031] The weight of sulfur feed is calculated as follows: the total weight of sulfur feed is calculated based on 30%wt of tin metal content in tin ore in the fuming furnace, and the excess coefficient is controlled at 5%~10%.

[0032] Preferably, the parameters of the pulverized coal conveying and injection system in step (3) are: pulverized coal feeding speed of 1.3~1.8t / h and conveying air pressure of 3~6Bar;

[0033] The particle size control requirements for the pulverized coal are as follows: passing through a 400-mesh sieve, fixed carbon content ≥65%wt, moisture content ≤2.5%wt, ash content ≤15%wt, and volatile matter ≤15%wt. Among these, passing through a 400-mesh sieve means that more than 90wt% of the total pulverized coal can pass through a 400-mesh sieve.

[0034] Preferably, step (3) further includes: after the molten slag contains ≤0.2% tin, stop the liquid sulfur suction pump, and simultaneously start the infrared heater of the liquid sulfur conveying pipeline to 80% power to heat up and melt the residual sulfur in the pipeline. After 5 minutes, close the check valve of the liquid sulfur conveying pipeline, and continue to keep the nitrogen conveying valve of the central pipeline open. When the temperature in the liquid sulfur conveying pipeline rises to a constant temperature of 130~150℃, open the purging nitrogen valve, keep the purging nitrogen pressure ≥3 Bar, and purge continuously for 3~5 minutes. After the residual sulfur in the pipeline melts, it flows back to the particulate sulfur. Inside the sulfur melting and heat preservation tank, the infrared heater of the liquid sulfur conveying pipeline can be stopped, the purging nitrogen valve can be closed, and the pulverized coal feed into the fuming furnace can be maintained. The pulverized coal feed rate can be adjusted to 0.5~1.0 t / h, while observing the temperature monitor to ensure that the temperature of the rising flue of the fuming furnace is between 1100~1150℃. If the temperature is lower or higher than this range, the coal feed rate can be increased or decreased by 0.1~0.3 t / h respectively until the slag in the fuming furnace is completely discharged. Then, the pulverized coal feed can be stopped, and the coal conveying air valve can be kept open to ensure that the coal injection burner is not blocked.

[0035] Preferably, in addition to using pulverized coal as the heat source for the fuming furnace and for the sulfidation-reduction process, piped natural gas, liquefied natural gas, or liquefied petroleum gas with the same calorific value can be used to replace pulverized coal, but the pressure of the gas at the burner end of the fuming furnace must be maintained above 4 Bar; in addition, lump coal can be mixed with the gas, but the lump coal needs to be transported into the fuming furnace through the top feed belt, and the lump coal is only used for the sulfidation-reduction process.

[0036] The apparatus used in the above method includes:

[0037] Granular sulfur screening and belt conveyor system, granular sulfur melting and heat preservation tank, liquid sulfur suction pump, liquid sulfur conveying pipeline, pulverized coal conveying and injection system, fuming furnace, slag water quenching system, waste heat boiler, surface cooler, bag dust collector and fuming furnace flue gas pipeline.

[0038] The granular sulfur screening and belt conveyor system is located on one side above the granular sulfur melting and heat preservation tank.

[0039] The liquid sulfur suction pump is connected to the granular sulfur melting and heat preservation tank and penetrates vertically into the interior of the granular sulfur melting and heat preservation tank;

[0040] The liquid sulfur suction pump, liquid sulfur conveying pipeline, fuming furnace, waste heat boiler, surface cooler, bag dust collector, and fuming furnace flue gas pipeline are connected in sequence.

[0041] The pulverized coal conveying and injection system and the slag water quenching system are respectively connected to the fuming furnace.

[0042] Preferably, the particulate sulfur screening and belt conveyor system includes:

[0043] Conical hopper for granular sulfur, conical hopper vibrator, primary screen, secondary screen, conical hopper discharge valve, intermediate silo, intermediate silo vibrator, intermediate silo discharge valve, differential weighing device, granular sulfur storage silo, storage silo discharge valve, granular sulfur conveyor belt.

[0044] The primary screen, the conical hopper for granular sulfur, the secondary screen, the discharge valve of the conical hopper, the intermediate silo, the discharge valve of the intermediate silo, the differential weighing device, the granular sulfur storage silo, and the discharge valve of the storage silo are connected in sequence from top to bottom.

[0045] The conical hopper vibrator is disposed on the side wall of the granular sulfur conical hopper; the intermediate silo vibrator is disposed on the side wall of the intermediate silo.

[0046] The feed end of the granular sulfur conveyor belt is located below the discharge valve of the storage silo, and the discharge end is located on one side above the granular sulfur melting and heat preservation tank.

[0047] Preferably, the granular sulfur melting and heat preservation tank is equipped with a heat preservation tank thermometer, a liquid level gauge, an infrared heating melter, and a feeding hopper;

[0048] The thermometer and level gauge of the heat preservation tank are both installed above the granular sulfur melting heat preservation tank and extend into the interior of the granular sulfur melting heat preservation tank; the infrared heating melter is installed in the wall surrounding the granular sulfur melting heat preservation tank; the feeding hopper is installed on one side above the granular sulfur melting heat preservation tank; the discharge end of the granular sulfur conveyor belt is located above the feeding hopper;

[0049] The liquid sulfur suction pump is equipped with a suction pump filter screen at the bottom.

[0050] Preferably, the outlet end of the liquid sulfur conveying pipeline has an inverted V-shaped structure; the liquid sulfur conveying pipeline is equipped with a liquid sulfur flow meter, a conveying pipeline pressure gauge, an infrared heater, a purging nitrogen pipe, a check valve, and a thermometer;

[0051] The infrared heater is installed inside the pipe wall of the liquid sulfur conveying pipeline;

[0052] The thermometer and the liquid sulfur flow meter are both installed on the side wall of the inlet end of the liquid sulfur conveying pipeline.

[0053] The pressure gauge for the conveying pipeline is installed in the pipeline on one side of the inlet end of the liquid sulfur conveying pipeline;

[0054] The purging nitrogen pipe is located at the top of the inverted V-shaped structure at the outlet end of the liquid sulfur conveying pipeline; the purging nitrogen pipe is equipped with a purging nitrogen pressure gauge and a purging nitrogen valve.

[0055] The check valve is located on one side of the outlet end of the liquid sulfur conveying pipeline.

[0056] Preferably, the pulverized coal conveying and injection system includes a pulverized coal tank and a pulverized coal conveying pipeline;

[0057] The pulverized coal tank is connected to the fuming furnace via a pulverized coal conveying pipeline;

[0058] The inlet end of the pulverized coal conveying pipeline is equipped with a coal feeding air valve, and a pulverized coal conveying flow meter is installed on one side of the inlet end.

[0059] Preferably, the fuming furnace includes: a liquid sulfur injection burner, a pulverized coal injection burner, a side liquid slag feed chute, a top feed inlet, a fuming furnace body, a temperature monitor, an observation hole, and a slag discharge port;

[0060] The liquid sulfur injection burner and the pulverized coal injection burner are respectively installed on both sides of the bottom of the fuming furnace body; the pulverized coal injection burner is installed at a height of 100mm above the bottom of the fuming furnace body, and the liquid sulfur injection burner is installed at a height of 100-150mm above the pulverized coal injection burner; the pulverized coal injection burner is connected to the pulverized coal conveying pipeline; the liquid sulfur injection burner is connected to the liquid sulfur conveying pipeline.

[0061] The slag discharge port is located on one side of the bottom of the fuming furnace body, and the slag discharge port is connected to the slag water quenching system.

[0062] The furnace-side liquid slag feed chute, temperature monitor, and observation hole are respectively installed on the upper side wall of the fuming furnace body;

[0063] The furnace top feed inlet is located on one side of the top of the fuming furnace body; a matching furnace top belt feeding system is provided above the furnace top feed inlet;

[0064] The fuming furnace body is sequentially connected to the waste heat boiler, the surface cooler, and the bag filter.

[0065] Preferably, the inlet end of the liquid sulfur injection burner is provided with a central nitrogen pipe; the central nitrogen pipe is connected to the liquid sulfur injection burner;

[0066] The inlet end of the central pipeline nitrogen pipe is equipped with a central pipeline nitrogen pressure gauge, a central pipeline nitrogen flow meter, and a central pipeline nitrogen valve.

[0067] Preferably, the above-mentioned device further includes: a flue gas monitor, a secondary air valve, and a dust collector;

[0068] The flue gas monitor is installed inside the flue gas duct of the fuming furnace;

[0069] The secondary air valve is located on the side wall at the bottom of the waste heat boiler;

[0070] The dust collector is located at the bottom between the waste heat boiler and the surface cooler, and is connected to the waste heat boiler and the surface cooler.

[0071] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0072] ① After being carefully selected, sulfur that meets the particle size standard is transported to the granular sulfur melting and heat preservation tank by a granular sulfur conveyor belt. This maintains the optimal melting and flow temperature of the sulfur and keeps the liquid sulfur suction pump in the correct position. This ensures the continuous and smooth transport of liquid sulfur through the pipeline and avoids the blockage that can easily occur when fine granular sulfur is directly transported and sprayed through the pipeline, resulting in fine powdery sulfur adhering to the inner wall of the transport pipeline.

[0073] ② Using pure nitrogen gas filtered by a dryer to transport particulate sulfur can avoid the ineffective consumption and waste of sulfur caused by the reaction of liquid sulfur with water to form hydrogen sulfide gas, which is contaminated by moisture in the pure nitrogen gas medium. It can also be used as an inert gas to protect liquid sulfur and its injection burner, avoiding the safety risks of liquid sulfur burning before being injected into the fuming furnace and the risk of burner burnout.

[0074] ③ Liquid sulfur is directly injected into the molten pool of the fuming furnace to complete the sulfidation-reduction process, which significantly improves the direct utilization rate of sulfur and avoids the waste caused by the high-difference material drop process of adding it to the molten pool via the furnace top belt, which is prone to direct combustion, as well as the pollution problem of hydrogen sulfide gas with a "rotten egg" smell generated at the tail end.

[0075] ④ Using liquid sulfur instead of traditional pyrite or granular sulfur as a sulfiding agent in a fuming furnace to fumigate and volatilize tin-containing materials can avoid the amount of iron brought into the fuming furnace by using pyrite. This not only affects the pH of the slag, but also requires the addition of quartz sand SiO2 to adjust the pH of the slag (see reaction 3). At the same time, it can also avoid the problem of blockage caused by direct pipeline transportation of granular sulfur, which will directly affect the effective hearth capacity of the fuming furnace, resulting in insufficient processing capacity of the fuming furnace per unit time.

[0076] ⑤ By rationally setting the positions of the liquid sulfur injection burner and the pulverized coal injection burner in the fuming furnace, the full progress of the sulfurization-reduction combined reaction can be ensured, and the optimal economic indicators of liquid sulfur and pulverized coal can be controlled.

[0077] ⑥ In addition to using pulverized coal as a reducing agent and for heating, this invention can also use pipeline natural gas, liquefied natural gas or liquefied petroleum gas with the same calorific value as alternatives, so as to achieve the same purpose as the sulfidation-reduction treatment method for tin-containing materials in the same fuming furnace, and realize the green use of clean energy. Attached Figure Description

[0078] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0079] Figure 1 is a structural diagram of the device provided by the present invention;

[0080] In the figure:

[0081] 1. Conical hopper for granular sulfur; 2. Conical hopper vibrator; 3. Primary screen; 4. Secondary screen; 5. Conical hopper discharge valve; 6. Intermediate silo; 7. Intermediate silo vibrator; 8. Intermediate silo discharge valve; 9. Differential weighing device; 10. Granular sulfur storage silo; 11. Storage silo discharge valve; 12. Granular sulfur conveyor belt; 13. Discharge hopper; 14. Thermometer for insulated tank; 15. Level gauge. 16. Liquid sulfur suction pump; 17. Granular sulfur melting and heat preservation tank; 18. Granular sulfur melting tank insulation layer; 19. Infrared heating melter; 20. Suction pump filter screen; 21. Liquid sulfur delivery pipeline; 22. Insulation layer; 23. Liquid sulfur flow meter; 24. Delivery pipeline pressure gauge; 25. Infrared heater; 26. Purge nitrogen pipe; 27. Purge nitrogen pressure gauge; 28. Purge nitrogen valve; 2 9. Check valve; 30. Central pipeline nitrogen pipe; 31. Liquid sulfur injection burner; 32. Liquid sulfur injection burner orifice; 33. Central pipeline nitrogen pressure gauge; 34. Central pipeline nitrogen flow meter; 35. Central pipeline nitrogen valve; 36. Pulverized coal tank; 37. Coal feeding and conveying air valve; 38. Pulverized coal conveying pipeline; 39. Pulverized coal conveying flow meter; 40. Pulverized coal injection burner; 41. Pulverized coal injection burner orifice; 4 2. Furnace-side liquid slag feed chute; 43. Furnace top conveyor belt feeding system; 44. Furnace top feed port; 45. Furnace body; 46. Temperature monitor; 47. Observation hole; 48. Secondary air valve; 49. Waste heat boiler; 50. Surface cooler; 51. Bag dust collector; 52. Flue gas monitor; 53. Dust unloader; 54. Slag discharge port; 55. Slag water quenching system; 56. Furnace flue gas pipeline; 57. Thermometer. Detailed Implementation

[0082] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Embodiment 1

[0083] This embodiment discloses a device for directly injecting liquid sulfur into a fuming furnace for sulfur volatilization, comprising:

[0084] The system includes a granular sulfur screening and belt conveyor system, a granular sulfur melting and heat preservation tank 17, a liquid sulfur suction pump 16, a liquid sulfur conveying pipeline 21, a pulverized coal conveying and injection system, a fuming furnace, a slag water quenching system 55, a waste heat boiler 49, a surface cooler 50, a bag dust collector 51, and a fuming furnace flue gas pipeline 56.

[0085] The liquid sulfur suction pump 16 is connected to the granular sulfur melting and heat preservation tank 17 and penetrates vertically into the interior of the granular sulfur melting and heat preservation tank 17.

[0086] The liquid sulfur suction pump 16, the liquid sulfur conveying pipeline 21, the fuming furnace, the waste heat boiler 49, the surface cooler 50, the bag dust collector 51, and the fuming furnace flue gas pipeline 56 are connected in sequence.

[0087] The pulverized coal conveying and injection system and the slag water quenching system 55 are respectively connected to the fuming furnace;

[0088] In this embodiment, the particulate sulfur screening and belt conveyor system includes:

[0089] 1. Conical hopper for granular sulfur; 2. Conical hopper vibrator; 3. Primary screen; 4. Secondary screen; 5. Conical hopper discharge valve; 6. Intermediate silo; 7. Intermediate silo vibrator; 8. Intermediate silo discharge valve; 9. Differential weighing device; 10. Granular sulfur storage silo; 11. Storage silo discharge valve; 12. Granular sulfur conveyor belt.

[0090] The primary screen 3, the granular sulfur conical hopper 1, the secondary screen 4, the conical hopper discharge valve 5, the intermediate silo 6, the intermediate silo discharge valve 8, the differential weighing device 9, the granular sulfur storage silo 10, and the storage silo discharge valve 11 are connected in sequence from top to bottom.

[0091] The conical hopper vibrator 2 is installed on the side wall of the granular sulfur conical hopper 1; the intermediate silo vibrator 7 is installed on the side wall of the intermediate silo 6;

[0092] The feed end of the granular sulfur conveyor belt 12 is located below the discharge valve 11 of the storage silo, and the discharge end is located on one side above the granular sulfur melting and heat preservation tank 17.

[0093] The granular sulfur melting and heat preservation tank 17 is equipped with a heat preservation tank thermometer 14, a liquid level gauge 15, an infrared heating melter 19, and a feeding hopper 13;

[0094] The thermometer 14 and the level gauge 15 of the heat preservation tank are both installed above the granular sulfur melting heat preservation tank 17 and extend into the interior of the granular sulfur melting heat preservation tank 17; the infrared heating melter 19 is installed in the wall around the granular sulfur melting heat preservation tank 17; the feeding hopper 13 is installed on one side above the granular sulfur melting heat preservation tank 17; the discharge end of the granular sulfur conveyor belt 12 is installed above the feeding hopper 13;

[0095] A passenger flow sulfur melting tank insulation layer 18 is formed above the liquid sulfur inside the granular sulfur melting and insulation tank 17;

[0096] The bottom of the liquid sulfur suction pump 16 is equipped with a suction pump filter screen 20.

[0097] The outlet end of the liquid sulfur conveying pipeline 21 has an inverted V-shaped structure; the liquid sulfur conveying pipeline 21 is equipped with a liquid sulfur flow meter 23, a conveying pipeline pressure gauge 24, an infrared heater 25, a purging nitrogen pipe 26, a check valve 29, and a thermometer 57.

[0098] An infrared heater 25 is installed inside the pipe wall of the liquid sulfur conveying pipeline 21 to form an insulation layer 22;

[0099] The thermometer 57 and the liquid sulfur flow meter 23 are both installed on the side wall of the inlet end of the liquid sulfur conveying pipeline 21.

[0100] The pressure gauge 24 for the conveying pipeline is installed in the pipeline on one side of the inlet end of the liquid sulfur conveying pipeline 21;

[0101] The purging nitrogen pipe 26 is located at the top of the inverted V-shaped structure at the outlet end of the liquid sulfur conveying pipeline 21; the purging nitrogen pipe 26 is equipped with a purging nitrogen pressure gauge 27 and a purging nitrogen valve 28.

[0102] The check valve 29 is located on one side of the outlet end of the liquid sulfur conveying pipeline 21.

[0103] Preferably, the pulverized coal conveying and injection system includes a pulverized coal tank 36 and a pulverized coal conveying pipeline 38;

[0104] The pulverized coal hopper 36 is connected to the fuming furnace via the pulverized coal conveying pipeline 38;

[0105] A coal conveying pipeline 38 is equipped with a coal conveying air valve 37 at the inlet end and a coal conveying flow meter 39 on one side of the inlet end.

[0106] Preferably, the fuming furnace includes: a liquid sulfur injection burner 31, a liquid sulfur injection burner orifice 32, a pulverized coal injection burner 40, a pulverized coal injection burner orifice 41, a side liquid slag feed chute 42, a top feed inlet 44, a fuming furnace body 45, a temperature monitor 46, an observation hole 47, and a slag discharge port 54.

[0107] Liquid sulfur injection burners 31 and pulverized coal injection burners 40 are respectively installed on both sides of the bottom of the fuming furnace body 45 and fixed through liquid sulfur injection burner holes 32 and pulverized coal injection burner holes 41; the pulverized coal injection burner 40 is installed at a height of 100mm from the bottom of the fuming furnace body 45, and the liquid sulfur injection burner 31 is installed at a height of 100~150mm above the pulverized coal injection burner 41; the pulverized coal injection burner 40 is connected to the pulverized coal conveying pipe 38; the liquid sulfur injection burner 31 is connected to the liquid sulfur conveying pipe 21.

[0108] The slag discharge port is located on one side of the bottom of the fuming furnace body 45, and the slag discharge port 54 is connected to the slag water quenching system 55;

[0109] The furnace-side liquid slag feed chute 42, temperature monitor 46, and observation hole 47 are respectively installed on the upper side wall of the fuming furnace body 45.

[0110] The furnace top feed inlet 44 is located on one side of the top of the fuming furnace body 45; a matching furnace top belt feeding system 43 is installed above the furnace top feed inlet 44;

[0111] The fuming furnace body 45 is connected in sequence to the waste heat boiler 49, the surface cooler 50, and the bag dust collector 51.

[0112] The inlet end of the liquid sulfur injection burner 31 is provided with a central nitrogen pipe 30; the central nitrogen pipe 30 is connected to the liquid sulfur injection burner 31.

[0113] The inlet end of the central pipeline nitrogen pipe 30 is equipped with a central pipeline nitrogen pressure gauge 33, a central pipeline nitrogen flow meter 34, and a central pipeline nitrogen valve 35.

[0114] In this embodiment, the above-mentioned device further includes: a flue gas monitor 52, a secondary air valve 48, and a dust collector 53;

[0115] The flue gas monitor 52 is installed inside the flue gas duct 56 of the fuming furnace;

[0116] The secondary air valve 48 is located on the side wall at the bottom of the waste heat boiler 49;

[0117] Dust collector 53 is located at the bottom between waste heat boiler 49 and surface cooler 50, and is connected to waste heat boiler 49 and surface cooler 50. Example 2

[0118] With 4m 2Taking the fuming furnace as the object, the amount of tin-containing material with a tin content of 5%wt that can be processed in a single furnace in 6 hours is 25 tons. According to theoretical calculation, the sulfur content of the sulfurizing agent required is 25 tons × 5%wt × 30% = 0.375 tons. Taking the excess coefficient as 5%, the total sulfur content is 0.375 × (1 + 5%) = 0.394 tons.

[0119] To this end, approximately 0.6 tons of purchased granular sulfur with a particle size between 2.8 and 6.0 mm and a sulfur content ≥99% was delivered to the granular sulfur storage silo 10. The sulfur was then conveyed into the granular sulfur melting and heat preservation tank 17 via the granular sulfur conveyor belt 12. The infrared heater 25 was turned on to heat and melt the granular sulfur, and the temperature of the liquid sulfur in the granular sulfur melting and heat preservation tank 17 was controlled at 130-150℃. It was confirmed that the liquid sulfur suction pump 16 was set at 1 / 3 of the height from the bottom of the tank, and the liquid sulfur in the granular sulfur melting and heat preservation tank 17 was always kept at 2 / 3 of the capacity. The nitrogen delivery valve 30 in the central pipeline was kept open, the nitrogen delivery pressure was maintained at 3 Bar, and the check valve 29 was kept closed.

[0120] After the tin ore in the fuming furnace is completely melted, i.e., the melt temperature is 1150℃, keep the nitrogen supply to the liquid sulfur injection burner 31 unobstructed, open the check valve 29 of the liquid sulfur delivery pipeline, and start the liquid sulfur suction pump 16 to inject liquid sulfur into the fuming furnace. For the first 10 minutes of feeding, start at 0 t / h and increase by 0.1 t / h every minute. That is, after 10 minutes of startup, the feeding rate of the liquid sulfur suction pump 16 will reach 1.0 t / h. Maintain this feeding rate within 1.0 ± 0.2 t / h with minor adjustments. When the liquid sulfur... When the sulfur feed rate (by weight) reaches 90% of the calculated amount, i.e., the liquid sulfur flow meter 23 shows that about 0.36 tons of sulfur have been delivered, a sample of molten slag inside the fuming furnace body 45 is taken by the sampling rod and sent for analysis. Once the tin content in the slag is ≤0.2%, the slag water quenching system 55 can be used for slag discharge and water quenching. If the tin content in the slag is higher than 0.2%, a sample of molten slag is taken every 1 minute and then sent for analysis. Once the tin content in the slag is ≤0.2%, the liquid sulfur suction pump 16 can be stopped, and the slag discharge port 54 can be opened immediately for slag discharge and water quenching.

[0121] While the liquid sulfur is continuously injected into the fuming furnace through the sulfur injection burner 31, the pulverized coal conveying and injection system is controlled to uniformly feed pulverized coal from the pulverized coal furnace 36 into the fuming furnace body 45, maintaining the pulverized coal feeding rate at 1.3t / h and the conveying air pressure at 3Bar to ensure a sulfurization-reduction atmosphere in the fuming furnace. At the same time, the flue gas monitor 52 at the outlet of the bag dust collector 51 is observed to ensure that the SO2 and CO concentrations in the flue gas during the sulfur injection and pulverized coal feeding processes are 0.9~1.5% and 7000~10000ppm, respectively. If the concentrations are lower or higher than these ranges, the sulfur and pulverized coal feed rates should be increased or decreased respectively, with fine adjustments within ±0.2t / h. The CO concentration can also be controlled within the above range by adjusting the opening of the secondary air valve 48 in the rising flue of the fuming furnace.

[0122] When the tin content of the molten slag in the fuming furnace body 45 is ≤0.2%, stop the liquid sulfur feeding and injection, i.e., stop the liquid sulfur suction pump 16. At the same time, start the infrared heater of the liquid sulfur conveying pipeline to 80% power to heat up and melt the residual sulfur in the pipeline. After 5 minutes, close the check valve 29 of the liquid sulfur conveying pipeline and keep the nitrogen valve 35 of the central pipeline normally open. When the temperature in the sulfur conveying pipeline 21 rises to a constant temperature of 130~150℃, open the purging nitrogen valve 28 and keep the purging nitrogen pressure ≥3 Bar. After purging continuously for 3~5 minutes, the residual sulfur in the pipeline melts and flows back to the particles. Inside the sulfur melting and heat preservation tank 17, the infrared heater 25 of the liquid sulfur conveying pipeline can be stopped, the purging nitrogen valve 28 can be closed, and the pulverized coal feed into the fuming furnace can be maintained. The pulverized coal feed rate can be adjusted to 0.5~1.0t / h, while observing the temperature monitor 46 to ensure that the temperature of the rising flue of the fuming furnace is 1100~1150℃. If it is lower or higher than this temperature range, the coal feed rate can be increased or decreased by 0.1~0.3t / h respectively until the slag in the fuming furnace is completely discharged. Then, the pulverized coal feed can be stopped, and the coal conveying air valve 37 can be kept open to ensure that the pulverized coal injection burner 40 is not blocked.

[0123] By observing the inside of the fuming furnace body 45 through the observation hole 47, and confirming that the slag inside the furnace has been completely discharged, the nitrogen valve 35 of the central pipeline and the coal conveying air valve 37 can be closed. After disassembling the sulfur injection burner 31 and the pulverized coal injection burner 40 for blockage inspection and cleaning, the burners can be reinstalled in their original positions. The nitrogen valve 35 of the central pipeline and the pulverized coal conveying air valve 37 should be kept open again, and their conveying air pressure should be kept stable above 3 Bar. Then the fuming furnace production operation can be started to enter the next cycle.

[0124] Sulfur injection burner 31 and pulverized coal injection burner 40 are respectively installed on both sides of the fuming furnace body 45. The pulverized coal injection burner 40 is installed 100mm above the bottom of the fuming furnace body 45, while the sulfur injection burner 31 is installed 100mm above the pulverized coal injection burner 40. Example 3

[0125] With 8m 2 Taking the fuming furnace as the object, the amount of tin-containing material with a tin content of 5%wt that can be processed in a single furnace in 6 hours is 50 tons. According to theoretical calculation, the sulfur content of the sulfurizing agent required is 50 tons × 5%wt × 30% = 0.75 tons. Taking the excess coefficient as 10%, the total sulfur content is 0.75 × (1 + 10%) = 0.825 tons.

[0126] To this end, approximately 1.24 tons of purchased granular sulfur with a particle size between 2.8 and 6.0 mm and a sulfur content ≥99% was delivered to the granular sulfur storage silo 10. The sulfur was then conveyed into the granular sulfur melting and heat preservation tank 17 via the granular sulfur conveyor belt 12. The infrared heater 25 was turned on to heat and melt the granular sulfur, and the temperature of the liquid sulfur in the granular sulfur melting and heat preservation tank 17 was controlled at 130-150℃. It was confirmed that the liquid sulfur suction pump 16 was set at 1 / 3 of the height from the bottom of the tank, and the liquid sulfur in the granular sulfur melting and heat preservation tank 17 was always kept at 2 / 3 of the capacity. The nitrogen delivery valve 30 in the central pipeline was kept open, the nitrogen delivery pressure was maintained at 3 Bar, and the check valve 29 was kept closed.

[0127] After the tin ore in the fuming furnace is completely melted, i.e., the melt temperature is 1150℃, keep the nitrogen supply to the liquid sulfur injection burner 31 unobstructed, open the check valve 29 of the liquid sulfur delivery pipeline, and start the liquid sulfur suction pump 16 to inject liquid sulfur into the fuming furnace. For the first 10 minutes of feeding, start at 0 t / h and increase by 0.1 t / h every minute. That is, after 10 minutes of startup, the feeding rate of the liquid sulfur suction pump 16 will reach 1.0 t / h. Maintain this feeding rate within 1.0 ± 0.2 t / h with minor adjustments. When the liquid sulfur... When the sulfur feed rate (by weight) reaches 90% of the calculated amount, i.e., the liquid sulfur flow meter 23 shows that about 0.36 tons of sulfur have been delivered, a sample of molten slag inside the fuming furnace body 45 is taken by the sampling rod and sent for analysis. Once the tin content in the slag is ≤0.2%, the slag water quenching system 55 can be used for slag discharge and water quenching. If the tin content in the slag is higher than 0.2%, a sample of molten slag is taken every 1 minute and then sent for analysis. Once the tin content in the slag is ≤0.2%, the liquid sulfur suction pump 16 can be stopped, and the slag discharge port 54 can be opened immediately for slag discharge and water quenching.

[0128] While the liquid sulfur is continuously injected into the fuming furnace through the sulfur injection burner 31, the pulverized coal conveying and injection system is controlled to uniformly feed pulverized coal from the pulverized coal furnace 36 into the fuming furnace body 45, maintaining the pulverized coal feeding rate at 1.3t / h and the conveying air pressure at 3Bar to ensure a sulfurization-reduction atmosphere in the fuming furnace. At the same time, the flue gas monitor 52 at the outlet of the bag dust collector 51 is observed to ensure that the SO2 and CO concentrations in the flue gas during the sulfur injection and pulverized coal feeding processes are 0.9~1.5% and 7000~10000ppm, respectively. If the concentrations are lower or higher than these ranges, the sulfur and pulverized coal feed rates should be increased or decreased respectively, with fine adjustments within ±0.2t / h. The CO concentration can also be controlled within the above range by adjusting the opening of the secondary air valve 48 in the rising flue of the fuming furnace.

[0129] When the tin content of the molten slag in the fuming furnace body 45 is ≤0.2%, stop the liquid sulfur feeding and injection, i.e., stop the liquid sulfur suction pump 16. At the same time, start the infrared heater of the liquid sulfur conveying pipeline to 80% power to heat up and melt the residual sulfur in the pipeline. After 5 minutes, close the check valve 29 of the liquid sulfur conveying pipeline and keep the nitrogen valve 35 of the central pipeline normally open. When the temperature in the sulfur conveying pipeline 21 rises to a constant temperature of 130~150℃, open the purging nitrogen valve 28 and keep the purging nitrogen pressure ≥3 Bar. After purging continuously for 3~5 minutes, the residual sulfur in the pipeline melts and flows back to the particles. Inside the sulfur melting and heat preservation tank 17, the infrared heater 25 of the liquid sulfur conveying pipeline can be stopped, the purging nitrogen valve 28 can be closed, and the pulverized coal feed into the fuming furnace can be maintained. The pulverized coal feed rate can be adjusted to 0.5~1.0t / h, while observing the temperature monitor 46 to ensure that the temperature of the rising flue of the fuming furnace is 1100~1150℃. If it is lower or higher than this temperature range, the coal feed rate can be increased or decreased by 0.1~0.3t / h respectively until the slag in the fuming furnace is completely discharged. Then, the pulverized coal feed can be stopped, and the coal conveying air valve 37 can be kept open to ensure that the pulverized coal injection burner 40 is not blocked.

[0130] By observing the inside of the fuming furnace body 45 through the observation hole 47, and confirming that the slag inside the furnace has been completely discharged, the nitrogen valve 35 of the central pipeline and the coal conveying air valve 37 can be closed. After disassembling the sulfur injection burner 31 and the pulverized coal injection burner 40 for blockage inspection and cleaning, the burners can be reinstalled in their original positions. The nitrogen valve 35 of the central pipeline and the pulverized coal conveying air valve 37 should be kept open again, and their conveying air pressure should be kept stable above 3 Bar. Then the fuming furnace production operation can be started to enter the next cycle.

[0131] Sulfur injection burner 31 and pulverized coal injection burner 40 are respectively installed on both sides of the fuming furnace body 45. The pulverized coal injection burner 40 is installed 100mm above the bottom of the fuming furnace body 45, while the sulfur injection burner 31 is installed 100mm above the pulverized coal injection burner 40. Example 4

[0132] With 16m 2 Taking the fuming furnace as the object, the amount of tin-containing material with a tin content of 11%wt that can be processed in a single furnace in 6 hours is 100 tons. According to theoretical calculation, the sulfur content of the sulfurizing agent required is 100 tons × 11%wt × 30% = 3.3 tons. Taking the excess coefficient as 10%, the total sulfur content is 3.3 × (1 + 10%) = 3.63 tons.

[0133] To this end, approximately 5.44 tons of purchased granular sulfur with a particle size between 2.8 and 6.0 mm and a sulfur content ≥99% were delivered to the granular sulfur storage silo 10. The sulfur was then conveyed into the granular sulfur melting and heat preservation tank 17 via the granular sulfur conveyor belt 12. The infrared heater 25 was turned on to heat and melt the granular sulfur, and the temperature of the liquid sulfur in the granular sulfur melting and heat preservation tank 17 was controlled at 130-150℃. It was confirmed that the liquid sulfur suction pump 16 was set at 1 / 3 of the height from the bottom of the tank, and the liquid sulfur in the granular sulfur melting and heat preservation tank 17 was always kept at 2 / 3 of the maximum capacity. The nitrogen delivery valve 30 in the central pipeline was kept open, the nitrogen delivery pressure was maintained at 3 Bar, and the check valve 29 was kept closed.

[0134] After the tin ore in the fuming furnace is completely melted, i.e., the melt temperature is 1150℃, keep the nitrogen supply to the liquid sulfur injection burner 31 unobstructed, open the check valve 29 of the liquid sulfur delivery pipeline, and start the liquid sulfur suction pump 16 to inject liquid sulfur into the fuming furnace. For the first 10 minutes of feeding, start at 0 t / h and increase by 0.1 t / h every minute. That is, after 10 minutes of startup, the feeding rate of the liquid sulfur suction pump 16 will reach 1.0 t / h. Maintain this feeding rate within 1.0 ± 0.2 t / h with minor adjustments. When the liquid sulfur... When the sulfur feed rate (by weight) reaches 90% of the calculated amount, i.e., the liquid sulfur flow meter 23 shows that about 0.36 tons of sulfur have been delivered, a sample of molten slag inside the fuming furnace body 45 is taken by the sampling rod and sent for analysis. Once the tin content in the slag is ≤0.2%, the slag water quenching system 55 can be used for slag discharge and water quenching. If the tin content in the slag is higher than 0.2%, a sample of molten slag is taken every 1 minute and then sent for analysis. Once the tin content in the slag is ≤0.2%, the liquid sulfur suction pump 16 can be stopped, and the slag discharge port 54 can be opened immediately for slag discharge and water quenching.

[0135] While the liquid sulfur is continuously injected into the fuming furnace through the sulfur injection burner 31, the pulverized coal conveying and injection system is controlled to uniformly feed pulverized coal from the pulverized coal furnace 36 into the fuming furnace body 45, maintaining the pulverized coal feeding rate at 1.3t / h and the conveying air pressure at 3Bar to ensure a sulfurization-reduction atmosphere in the fuming furnace. At the same time, the flue gas monitor 52 at the outlet of the bag dust collector 51 is observed to ensure that the SO2 and CO concentrations in the flue gas during the sulfur injection and pulverized coal feeding processes are 0.9~1.5% and 7000~10000ppm, respectively. If the concentrations are lower or higher than these ranges, the sulfur and pulverized coal feed rates should be increased or decreased respectively, with fine adjustments within ±0.2t / h. The CO concentration can also be controlled within the above range by adjusting the opening of the secondary air valve 48 in the rising flue of the fuming furnace.

[0136] When the tin content of the molten slag in the fuming furnace body 45 is ≤0.2%, stop the liquid sulfur feeding and injection, i.e., stop the liquid sulfur suction pump 16. At the same time, start the infrared heater of the liquid sulfur conveying pipeline to 80% power to heat up and melt the residual sulfur in the pipeline. After 5 minutes, close the check valve 29 of the liquid sulfur conveying pipeline and keep the nitrogen valve 35 of the central pipeline normally open. When the temperature in the sulfur conveying pipeline 21 rises to a constant temperature of 130~150℃, open the purging nitrogen valve 28 and keep the purging nitrogen pressure ≥3 Bar. After purging continuously for 3~5 minutes, the residual sulfur in the pipeline melts and flows back to the particles. Inside the sulfur melting and heat preservation tank 17, the infrared heater 25 of the liquid sulfur conveying pipeline can be stopped, the purging nitrogen valve 28 can be closed, and the pulverized coal feed into the fuming furnace can be maintained. The pulverized coal feed rate can be adjusted to 0.5~1.0t / h, while observing the temperature monitor 46 to ensure that the temperature of the rising flue of the fuming furnace is 1100~1150℃. If it is lower or higher than this temperature range, the coal feed rate can be increased or decreased by 0.1~0.3t / h respectively until the slag in the fuming furnace is completely discharged. Then, the pulverized coal feed can be stopped, and the coal conveying air valve 37 can be kept open to ensure that the pulverized coal injection burner 40 is not blocked.

[0137] By observing the inside of the fuming furnace body 45 through the observation hole 47, and confirming that the slag inside the furnace has been completely discharged, the nitrogen valve 35 of the central pipeline and the coal conveying air valve 37 can be closed. After disassembling the sulfur injection burner 31 and the pulverized coal injection burner 40 for blockage inspection and cleaning, the burners can be reinstalled in their original positions. The nitrogen valve 35 of the central pipeline and the pulverized coal conveying air valve 37 should be kept open again, and their conveying air pressure should be kept stable above 3 Bar. Then the fuming furnace production operation can be started to enter the next cycle.

[0138] Sulfur injection burner 31 and pulverized coal injection burner 40 are respectively installed on both sides of the fuming furnace body 45. The pulverized coal injection burner 40 is installed at a height of 100mm above the bottom of the fuming furnace body 45, while the sulfur injection burner 31 is installed at a height of 100mm above the pulverized coal injection burner 40.

[0139] Comparative Example 1

[0140] With 4m 2 Taking the fuming furnace as an example, with all other conditions unchanged, and using pyrite with a sulfur content of about 35%, it also contains 50% iron and has a moisture content of 10%. Taking the excess coefficient as 5%, the total sulfur content is 0.394 tons. Therefore, the amount of pyrite needed is 0.394 ÷ 35% = 1.13 tons.

[0141] The pyrite was conveyed into the molten pool of the fuming furnace via a conveyor belt at the top of the furnace to participate in the sulfidation-reduction reaction. After 1.13 tons of pyrite were completely fed into the furnace, the fuming furnace was kept in fuming and volatilization operation for 10 minutes. After sampling and analysis, the slag contained 0.5% wt tin, and the fuming effect was not good. Another 0.07 tons of pyrite needed to be fed into the fuming furnace for fuming and volatilization to ensure that the tin content of the slag was below 0.2%. The slag was discharged through the slag outlet for water quenching. The water vapor after water quenching had a "rotten egg" smell. Obviously, the amount of pyrite used exceeded the theoretical value, the reaction was incomplete, and a lot of waste occurred. In addition, in the sulfidation-reduction process, according to the slag-forming reaction (3), about 0.3 tons of 96% grade quartz sand also needed to be added, which increased the operating load and cost of the fuming furnace.

[0142] Comparative Example 2

[0143] With 8m 2 Taking the fuming furnace as an example, with all other conditions unchanged, and using pyrite with a sulfur content of about 35%, it also contains 50% iron and has a moisture content of 10%. Taking the excess coefficient as 10%, the total sulfur content is 0.825 tons. Therefore, the amount of pyrite needed is 0.825 ÷ 35% = 2.36 tons.

[0144] The pyrite was conveyed into the molten pool of the fuming furnace via a conveyor belt at the top of the furnace to participate in the sulfidation-reduction reaction. After 2.36 tons of pyrite were completely fed into the furnace, the fuming furnace was kept in fuming and volatilization operation for 10 minutes. After sampling and analysis, the slag contained 0.48% wt tin, and the fuming effect was not good. Another 0.15 tons of pyrite needed to be fed into the fuming furnace for fuming and volatilization to ensure that the tin content of the slag was below 0.2%. The slag was discharged through the slag outlet for water quenching. The water vapor after water quenching had a "rotten egg" smell. Obviously, the amount of pyrite used exceeded the theoretical value, the reaction was incomplete, and a lot of waste occurred. In addition, in the sulfidation-reduction process, according to the slag-forming reaction (3), about 0.6 tons of 96% grade quartz sand also needed to be added, which increased the operating load and cost of the fuming furnace.

[0145] Comparative Example 3

[0146] With 16m 2Taking the fuming furnace as an example, with all other conditions unchanged, and using pyrite with a sulfur content of about 35%, it also contains 50% iron and has a moisture content of 10%. Taking the excess coefficient as 10%, the total sulfur content is 3.63 tons. Therefore, the amount of pyrite needed is 3.63 ÷ 35% = 10.4 tons.

[0147] The pyrite was conveyed into the molten pool of the fuming furnace via a belt conveyor at the top of the furnace to participate in the sulfidation-reduction reaction. After 10.4 tons of pyrite were completely fed into the furnace, the fuming furnace was kept in fuming and volatilization operation for another 10 minutes. Samples were taken for analysis, and the slag contained 0.7% wt tin. The fuming effect was not good. Another 0.47 tons of pyrite needed to be fed into the fuming furnace for fuming and volatilization to ensure that the tin content of the slag was below 0.2%. The slag was discharged through the slag outlet for water quenching. The water vapor after water quenching had a "rotten egg" smell. Obviously, the amount of pyrite used exceeded the theoretical value, the reaction was incomplete, and a lot of waste occurred. In addition, the sulfidation-reduction process also required the addition of about 2.89 tons of 96% grade quartz sand according to the slag-forming reaction (3), which increased the operating load and cost of the fuming furnace.

[0148] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0149] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for directly injecting liquid sulfur into a fuming furnace for sulfur volatilization, characterized in that, The steps include: (1) sending purchased granulated sulfur to the granulated sulfur storage silo, and then feeding the sulfur into the granulated sulfur melting and heat preservation tank through the granulated sulfur feeder; heating the granulated sulfur melting and heat preservation tank to melt the granulated sulfur, and controlling the temperature of the liquid sulfur in the granulated sulfur melting and heat preservation tank to maintain the temperature at 130~150℃; setting a liquid sulfur suction pump at a height of 1 / 3 from the bottom of the heat preservation tank to always maintain the molten liquid sulfur in the granulated sulfur melting and heat preservation tank at 2 / 3 of the high capacity; (2) after the tin ore in the fuming furnace is completely melted, feeding nitrogen through the central pipeline to Nitrogen gas is supplied into the fuming furnace, maintaining a stable pressure of 3-6 Bar. Simultaneously, a liquid sulfur suction pump is activated to inject liquid sulfur into the furnace. When the weight of the liquid sulfur feed reaches 90% of the calculated amount, a sample of the molten slag is taken from the furnace and sent for analysis. Once the tin content in the slag is ≤0.2%, the liquid sulfur suction pump is stopped, and the slag can be discharged into the slag water quenching system. If the tin content in the slag is higher than 0.2%, a sample of the molten slag is taken every 1 minute and sent for analysis. Once the tin content in the slag is ≤0.2%, the liquid sulfur suction pump is stopped, and the slag outlet of the fuming furnace is immediately opened. (3) While injecting liquid sulfur into the fuming furnace in step (2), feed pulverized coal evenly into the fuming furnace through the pulverized coal conveying and injection system. At the same time, observe the flue gas monitoring situation to ensure that the SO2 and CO concentrations in the flue gas during the liquid sulfur injection and pulverized coal feeding process are 0.9~1.5% and 7000~10000ppm, respectively. If the concentrations are lower or higher than the range, the liquid sulfur and pulverized coal feed rates should be increased or decreased respectively, with adjustments within ±0.2t / h. Alternatively, the CO concentration can be controlled within the above range by adjusting the opening of the secondary air valve. Within the interval; (4) Check the situation inside the fuming furnace. After confirming that the slag inside the furnace has been completely discharged, the nitrogen supply, coal supply air supply and liquid sulfur supply can be shut off. After disassembling the liquid sulfur injection burner and pulverized coal injection burner on the fuming furnace and checking and cleaning the burner blockage, the liquid sulfur injection burner and pulverized coal injection burner can be reinstalled in their original positions. Keep the nitrogen supply and pulverized coal supply air constantly open again, keep the liquid sulfur supply closed, and keep the nitrogen supply pressure and pulverized coal supply air pressure stable at 3~6 Bar. Then the fuming furnace production operation can be started to enter the next cycle.

2. The method for directly injecting liquid sulfur into a fuming furnace for sulfidation and volatilization according to claim 1, characterized in that, In step (1), the purchased sulfur contains ≥99% sulfur and the particle size of the purchased granular sulfur is between 2.8 and 6.0 mm; in step (2), the nitrogen gas is pure nitrogen gas and the water content of the pure nitrogen gas is ≤0.5%.

3. The method for directly injecting liquid sulfur into a fuming furnace for sulfidation and volatilization according to claim 1, characterized in that, The parameters of the liquid sulfur suction pump mentioned in step (2) are as follows: within 10 minutes of starting the feed head, the feed rate is increased by 0.1 t / h every minute, starting from 0 t / h. That is, after 10 minutes of starting, the feed rate of the liquid sulfur suction pump will reach 1.0 t / h. The feed rate is maintained within 1.0 ± 0.2 t / h and finely adjusted. The weight of the sulfur feed is calculated by the following method: the total weight of the sulfur feed is calculated based on 30% wt of tin metal content in the tin ore in the fuming furnace, and the excess coefficient is controlled at 5%~10%.

4. The method for direct injection of liquid sulfur into a fuming furnace for sulfidation and volatilization according to claim 1, characterized in that, The parameters of the pulverized coal conveying and injection system in step (3) are: pulverized coal feeding speed of 1.3~1.8t / h, and conveying air pressure of 3~6Bar; the particle size control requirements of the pulverized coal are: passing through a 400-mesh sieve, fixed carbon content ≥65%wt, moisture content ≤2.5%wt, ash content ≤15%wt, volatile matter ≤15%wt, wherein passing through a 400-mesh sieve means that more than 90wt% of the total pulverized coal can pass through a 400-mesh sieve.

5. The method for direct injection of liquid sulfur into a fuming furnace for sulfidation and volatilization according to claim 1, characterized in that, Step (3) also includes: after the molten slag contains ≤0.2% tin, stop the liquid sulfur suction pump, and at the same time start the infrared heater of the liquid sulfur conveying pipeline to 80% power to heat up and melt the residual sulfur in the pipeline. After 5 minutes, close the check valve of the liquid sulfur conveying pipeline. The nitrogen conveying pipeline is in the normally open state. When the temperature in the liquid sulfur conveying pipeline rises to 130~150℃ and remains constant, purge with nitrogen and maintain the pressure of the purging nitrogen ≥3 Bar. After purging continuously for 3~5 minutes, the residual sulfur in the pipeline melts and flows back to the granular sulfur melting and maintenance. Once the heating tank is in the warming tank, the heating of the heat preservation tank can be stopped, the purging nitrogen can be stopped, and the pulverized coal feed into the fuming furnace can be maintained. The pulverized coal feed rate should be adjusted to 0.5~1.0 t / h, while observing the temperature monitor to ensure that the temperature of the rising flue of the fuming furnace is between 1100~1150℃. If the temperature is lower or higher than this range, the coal feed rate should be increased or decreased by 0.1~0.3 t / h respectively until the slag in the fuming furnace is completely discharged. Then, stop feeding pulverized coal and keep the coal feeding air valve in the open position to ensure that the coal feeding and purging burners are not blocked.

6. The method for direct injection of liquid sulfur into a fuming furnace for sulfidation and volatilization according to claim 1, characterized in that, In step (1), an infrared heating melter is installed in the walls around the granular sulfur melting and heat preservation tank, and the granular sulfur melting and heat preservation tank is heated by the infrared heating melter.

7. The method for direct injection of liquid sulfur into a fuming furnace for sulfidation and volatilization according to claim 1, characterized in that, In step (2), the central nitrogen pipe is connected to the fuming furnace via a liquid sulfur injection burner; the liquid sulfur suction pump is connected to the liquid sulfur injection burner via a liquid sulfur delivery pipe; wherein the central nitrogen pipe and the liquid sulfur injection burner are on the same horizontal line; and the liquid sulfur delivery pipe and the central nitrogen pipe form an acute angle.

8. The method for direct injection of liquid sulfur into a fuming furnace for sulfidation and volatilization according to claim 1, characterized in that, The pulverized coal conveying and injection system in step (3) includes a pulverized coal tank and a pulverized coal conveying pipeline; the pulverized coal tank is connected to the pulverized coal injection burner through the pulverized coal conveying pipeline; a coal feeding and conveying air valve is provided at the inlet end of the pulverized coal conveying pipeline, and a pulverized coal conveying flow meter is provided on one side of the inlet end.

9. The method for direct injection of liquid sulfur into a fuming furnace for sulfidation and volatilization according to claim 8, characterized in that, In step (4), the liquid sulfur injection burner and the pulverized coal injection burner are respectively installed on both sides of the bottom of the fuming furnace; the pulverized coal injection burner is installed at a height of 100mm above the bottom of the fuming furnace, and the liquid sulfur injection burner is installed at a height of 100~150mm above the pulverized coal injection burner; the pulverized coal injection burner is connected to the pulverized coal conveying pipeline.

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